USMC Rifles in Use

A friend's teenage son asked me what M16 variants are currently in use. I figured it was the M16A4 with the M16A3 in some support and training roles. Did a google search but can't tie it down, so I thought some of you guys who had served in the recent past might have the answer.

The way its typically set up right now, most troops get the M16A4 with a Trijicon ACOG on it, Motor T Operators, SNCOs, Zeros, and really short people get M4 with same optics. We train with the rifle we deploy with, so M16A4 and M4s, M9s, M249s and the occasional M27 or M416 are there too. HTH